The use of torque discs in the transmission of torque between, for example, a pair of generally coaxially arranged rotating shafts or the like is well known, the torque disc being able to flex slightly to accommodate small amounts of misalignment between the shafts. A range of materials are used in such torque discs, for example rubber-like materials have been used in this type of application. It is becoming increasingly common to use composite materials in such torque discs. The use of composite materials is advantageous in that the materials are of high strength whilst also being relatively low in weight.
GB2401923 describes a composite material torque disc which is composed of a plurality of layers of a woven fibrous material, for example of carbon fibre form, embedded within a polymer matrix material. The layers of woven fibrous material are angularly displaced from one another so as to enhance the strength and ability of the torque disc to withstand loadings in a range of different directions.
Typically, the torque disc is secured to the rotating shafts or the like with which it is used by a series of fasteners, for example in the form of screw threaded bolts. The bolts pass through respective openings formed in the torque disc. It is important to ensure that the parts of the torque disc through which or in which the openings are formed are of sufficient strength to be able to withstand the loadings applied thereto, in use. The provision of openings in composite materials weakens the material and so may limit their suitability for use in torque disc applications.
It is an object of the invention, therefore, to provide a composite material torque disc of enhanced strength, particularly in the regions thereof to be secured to other components.